Hydraulically operated machine and control system therefor



" y 7, 1969 w. L. GOVAN 3,446,053

HYDRAULICALLY OPERATED MACHINE) AND CONTROL SYSTEM THEREFOR Filed May 2, 1966 Sheet 1 of 3 'FlG. 2

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L 8 33 N r1 HE Z 93 Z w m IN VENTOR. WILLIAM L. GOVAN ATTORNEf i V May 27, 1969 w. L. GOVAN 3,446,053

HYDRAULICALLY OPERATED MACHINE AND CONTROL Filed May 2, 1966 SYSTEM THEREFOR Sheet 2 of3 1 B 30 v l I00 I 28 SLS-I 02 n6 I09 'lI 82 so me l I -I MRLS-4 KY3 EPMRLS-S IoI MRLS-3 MRLS-G I23 QINVENTOR. G 3 WILLIAM L. GOVAN BY W ' ATTORNE i y 1969 w. L. GOVAN 3,446,053

HYDRAULICALLY OPERATED MACHINE AND CONTROL SYSTEM THEREFOR Filed May 2, 1966 Sheet 3 of 3 CRG-l I NVEN TOR.

WILLIAM L GOVAN BY ATTORNEY I z United States Patent 3,446,053 HYDRAULICALLY OPERATED MACHINE AND CONTROL SYSTEM THEREFOR William L. Govan, Rochester, N.Y., assignor to Farrel Corporation, Rochester, N.Y., a corporation of Connecticut Filed May 2, 1966, Ser. No. 546,820 Int. Cl. B30b 11/30 U.S. Cl. 72-253 11 Claims ABSTRACT OF THE DISCLOSURE An extrusion press is disclosed in which both the ram and the billet container are reciprocable to and from the die; and the ram is reciprocated by a main hydraulicallyoperated piston and by two auxiliary pistons disposed at opposite sides, respectively, of the main piston. Mounted in each auxiliary piston is a rod which engages the container, to transmit forward motion of the ram to the container until the container engages the die. Thereafter the ram moves forwardly independent of the container to force the billet through the die. Then two hydraulicallyoperated pistons return the container with the ram to the starting position of the container. Then the ram is retracted to its starting position by its pistons.

This invention relates to hydraulically operated machines, and more particularly to hydraulically-operated extrusion presses.

In metal extrusion presses it has been customary heretofore to move the billet container axially into engagement with the die, then to load the billet, and then to advance the ram into engagement with the billet to force the billet into the container and through the die. This method of operation, however, does not afford much time to inspect, clean and lubricate the die.

For this reason it is desirable to program the operation of the press so that the billet is raised and pushed into the container by advance of the main ram, then the container and main ram move toward the die together to push the loaded container against the die and to extrude the billet through the die.

One object of this invention is to provide a system usable in an extrusion press or any similar hydraulically operated machine, for synchronizing the movements of the main ram and container in either or both directions for at least a portion of their strokes.

Another object of this invention is to provide a system of the type described, wherein at the end of the synchronized movement the distance between the two com ponents may be increased or decreased.

A further object of this invention is to provide, for hydraulically operated machines of the type described, an improved control system which increases the efliciency of the machine operation without requiring any increase in the capacity of the pumps that power the machines hydraulic system.

Another object of the invention is to provide means for actuating the two synchronousl -operated parts of the machine in a fast cycle with minimum sized pumps. To this end a further object of the invention is to actuate the two synchronously moving parts so that the speed of motion of the leading machine part may be the same as for the trailing part without any increase of pump capacity.

A more specific object of this invention is to provide an improved system for synchronizing the movements of the container and ram in a hydraulically operated extrusion press, so that the billet may be pushed into the container before the container itself is pushed against the die, thereby to afford more time for inspecting, cleaning and lubricating the die.

A still further object of this invention is to provide a hydraulic cushion between the synchronously moving parts to prevent direct impact.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims particularly when read in conjunction with the accompanying drawings.

The purposes of the invention are accomplished by adding one or more small pusher rams either to the main ram or to the container. In the embodiment of the invention herein disclosed, for convenience these two single acting rams are incorporated within the hollow piston rods of the two auxiliary side cylinders which advance and return the main ram. These pusher rams extend towards the container. A head on the inner end of each pusher ram limits its free outward stroke. When the main ram and container approach each other, the first point of contact is between the outer ends of these pusher rams and the container housing. The motive fluid is trapped behind the pusher rams to provide a hydraulic cushion, and to lock the pusher rams in position so that the main ram then forces the container to move with it in the forward direction and the container forces the main ram to move with the container on the return. The pusher rams are continuously connected to low pressure (pilot pressure) through a check valve. This extends the pusher rams with low force whenever they are not forced back by the container. The check valve prevents back flow and locks the pusher rams in extended position. A relief valve permits the pusher rams to be forced in when the pressure overcomes the relief valve setting. This occurs, for instance, when the container is against the die and can move no further forward, but the main ram is continuing to advance. The relief valve is set just high enough to overcome the resistance to motion of the container or main ram, respectively, when the respective part is free to move. The low ptessure used to extend the pusher rams should be insuflicient to move the container or the main ram, respectively.

In the hydraulic circuit illustrated in the accompanying drawings, a solenoid-controlled, pilot operated, two-way valve is used in the low-pressure line to control the time at which the pusher rams are extended. This, however, is not essential.

Moreover, while the invention is disclosed in connection with an extrusion press, it will be understood it may be applied to any machine in which two independent hydraulically-operated parts move in the same direction during part, at least, of the machine cycle.

In the drawings:

FIG. 1 is a plan view of an extrusion press made in accordance with one embodiment of this invention, parts thereof being cutaway and shown in section;

FIG. 2 is an enlarged sectional view taken along the line 22 in FIG. 1 looking in the direction of the arrows;

FIG. 3 is a diagram of the electrically controlled hydraulic system of this press; and

FIG. 4 is an electrical diagram illustrating one manner in which the hydraulic system may be controlled.

The press illustrated in FIGS. 1 and 2 is generally similar to that disclosed in my US. Patent No. 3,194,037, granted July 13, 1965.

Referring now to the drawings by numerals of reference, 12 denotes the base or frame of the machine, 13 a catwalk which surrounds an elevated platform 103 located above one end of the base. Beneath this platform are mounted an oil sump or reservoir 102, and the main ram cylinder 14 in which the main ram piston 16 reciprocates, all shown diagrammatically in FIG. 3. At

its outer end this piston is connected to the cross head 17, which carries the main ram extrusion stem 18. At opposite sides of cylinder 14 are two positioning cylinders 22, which contain pistons 23 that are connected (FIG. 3) through their rods 24 to cross head 17 to reciprocate the ram stem 18. A conventional billet loader 34 (FIGS. 1 and 3) is positioned between the press ways and is operated by cylinder 35 (FIG. 3). Mounted in a conventional manner on the end platen 26 is a cylinder 30 (FIGS. 1 and 3) for operating the shear 28 (FIG. 3). The end platen 26 is secured by tie bolts 25 to the frame of the press.

The container housing 37, which is mounted to slide on the press ways 20, is secured adjacent opposite sides thereof by nuts 38 against shoulders on two, spaced, parallel piston rods 39. The rods 39 are connected to the pistons 41 which slide in spaced, parallel cylinders 42 that are secured in the platen 26. At its left end (FIG. 1) each cylinder 42 is sealed by a cap 43, and adjacent its other end is formed with an internal shoulder 44, which limits movement of the container housing 37 to the right. Annular gasket or seals 46 prevent leakage from the cylinders along the piston rods 39. A radial port 48 in the wall of cylinder 42 supplies and exhausts the motive fluid to and from the right end (FIG. 1) of each cylinder 42. An axial port 49 in each cap 43 supplies and exhausts the motive fluid to and from the other end of each cylinder 42.

Referring now to FIG. 2, each slide or positioning cylinder 22 is secured in a bracket 51 (only one of which is illustrated in FIG. 2); and each cylinder 22 is closed at its rear or right end by a cap 53, which is secured by screws 54 to a ring 55 that is threaded onto the rear end of the cylinder. Each cap 53 has an axial port therethrough that communicates with the right end of the cylinder. In each cylinder the associated piston rod 24 projects at its forward end slidably through a bushing 63, which is secured by a cap 64 and screws 65 to the forward end of the cylinder.

Adjacent its forward end each cylinder 22 is formed with an internal shoulder 67, which is engageable by the associated piston 23 to limit the forward movement of its rod 24. Annular packing and bushing elements 68 help prevent leakage from each cylinder along its piston rod 24. Just rearwardly of its shoulder 67, each cylinder 22 is provided with a radial port 71, which communicates with the forward or left end of the cylinder. Port 71 is connected by fitting 72 with the fluid supply.

At its forward end each piston rod 24 is of reduced diameter. The reduced diameter portions 74 of the rods 24 extend through the crosshead 17 adjacent opposite sides thereof, and are secured to the crosshead by nuts 76. A spacer or washer 78 is interposed between the crosshead 17 and an external shoulder 79 formed on each rod 24 by its reduced diameter portion 74.

Mounted to reciprocate in a blind bore 80, formed in the forward end of each rod 24 coaxially thereof, is a pusher rod or ram 82. Adjacent its forward end each rod 82 slides in a pair of axially spaced, guide bushings 83 and 84, which are secured in the forward end of each rod 24 by an annular cap 85 and screws 86. At its inner end each rod 82 is provided with an enlarged diameter head 94, which is engageable with the inner end of the associated bearing 83 to limit the forward movement of the rod. At its outer, forward end each rod is formed with a pusher head 95, which is engageable with the container 37.

There is a radial port 91 in each rod 24, which communicates at its inner end with the bore 80 of the rod,

and which is connected at its outer end through a fitting main ram. The pump output ports A and B are connected to lines and 101, respectively; and the pumps are also connected conventionally to the reservoir 102.

The lines 100, 101 are connected by a conventional, solenoid-controlled, pilot operated, spring-returned valve 105, which i controlled by a solenoid 106. Valve 105 connects lines 100 and 101 in its returned position and disconnects them in its actuated position. Line 100 is also connected through a conventional, two-way, solenoid-controlled valve 107, which is controlled by a sole noid 108, and by a line 109 to each of the ports 71 in the positioning cylinders 22. Line 100 is also connected through a conventional, four-way valve 110 either to lines 98 and 99 and the ports 48 in the right ends of the container positioning cylinders 42, or to lines 113 and 114 and ports 49 at the left ends of these cylinders. Valve 110 is also connected by line 115 to the reservoir 102. Valve 110 is controlled by solenoids 111 and 112.

The line 101 is connected through a conventional twoway valve 116, which is controlled by a solenoid 117, and lines 118 and 119 with the ports 60 formed in the rear or right ends (FIGS. 1 and 3) of the main ram side cylinders 22. A line 120 and a valve 121, which is controlled by a solenoid 122, also connects line 101 with line 109 and ports 71 in the left ends of cylinders 22. Line 101 is also connected through a conventional prefill valve PV and a line 123 with port 124 in the rear or right hand end of main ram cylinder 14. The construction and operation of valve PV is disclosed in my above-noted U.S. Patent No. 3,194,037, and will not, therefore, be described in further detail herein.

Fluid at a relatively low or pilot pressure P.P. may be applied through a conventional two-way valve 125, which is operated by a solenoid 126, and lines 127 and 128 to the ports 91 formed in the forward ends of the bores in piston rods 24 which contain the pusher rams 82. A presettable relief valve 129 is connected at one side to the line 127, and at its opposite side to the reservoir 102. A check valve 130 is mounted in line 127 between the valves 125 and 129.

Two conventional four-way valves 134 and 131 control, respectively, the operations of the shear through cylinder 30, and of the billet loader through cylinder 35, respectively. Valves 134 and 131 are operated by solenoids 132 and 133, respectively. The hydraulic system is provided also with conventional filters, gauges, check valves, and other solenoid operated valves (not illustrated), that may be necessary to operate in a conventional manner other elements of the press. Illustrated also in FIG. 3 are a number of limit switches, which are operable in a predetermined manner by the cross head 17, the container 37, the shear 28 and the loader 34, as will be described in more detail below.

In FIG. 4 a plurality of circuits are shown connected across a power source represented by the lines L and L It will be understood that FIG. 4 illustrates only those circuits which are pertinent to this invention. Switches MRLS-l, MRLS-2, MRLS-3, MRLS-4 and MRLS-S (FIGS. 3 and 4) are main ram limit switches, which are operated by the crosshead 17. Switch LLS-l (FIGS. 3 and 4) is a loader limit switch which is operated by the billet loader 34. Switches CLS-l, CLS-2 and CLS-3 (FIGS. 3 and 4) are container limit switches, which are operated by a rod (FIG. 3), which is secured to the container housing 37 for movement therewith. Switches SLS1 and SLS-2 (FIGS. 3 and 4) are limit switches, which are operated by the shear 28. Relays CR1, CR2, CR3, CR4 and CR5 are switching relays for controlling sequential operation of the press. Relay CRP is a relay which controls the output of the pumps P.

When the press is at rest, the main ram stem 18, the shear 28 and the loader 34 are retracted, and the container housing 37 is spaced from the die (not illustrated) toward the direction of the main ram stem 18. At this time the normally-closed limit switches MRLS4 and MRLS-S are held open by the cross head 17; and normally-closed switch SLS-1 is held open by the shear 28; and the normally-closed switch CLS-3 is held open by the rod 140 on container housing 37.

To operate the press the operator depresses the pushbutton PB1 momentarily, thereby energizing relay CR1 and solenoids 133 and 126- through the normally-closed limit switch MRLS-l. Relay CR1 closes the holding switch CR1*1 to hold the relay CR1 and the solenoids 133 and 126 energized upon release of pushbutton PB-1. The now energized solenoid 126 shifts valve 125 so that hydraulic motive fluid passes through the check valve 130, lines 127 and 128, and ports 91 (FIG. 2 into the bores 80 in the piston rods 24 and behind the heads 94 of rams 82, causing the latter to advance. At the same time the energized solenoid 133 shifts the valve 131 so that hydraulic fluid under pressure is admitted to the cylinder 35 to actuate the loader 34 to raise a billet into registry with the container in housing 37. The raised loader 34 closes temporarily the normally-open limit switch LLS1 (FIGS. 3 and 4) simultaneously to energize the relays CR2, CRP, and the solenoids 117 and 106 through the normally-closed limit switch MRLS-2. Relay CR2 closes switch CR24 to energize solenoid 108, and solenoid 122 through the normally-closed switch CR6-2.

The now-energized solenoids 117 and 106 open and close, respectively, the valves 116 and 105; and, the nowenergized pump control relay CRP causes fluid to flow from the ports B in the pumps P to the line 101, and through valve 116 and lines 118 and 119 to the rear or right ends of the side cylinders 22. The main ram- 18 thus begins to advance, thereby allowing switches MRLS- 4 and MRLS-S to close, and at the same time commencing to push the raised billet into the container in housing 37. At this time the valve 107 is closed, and valve 121 is open, so that fluid, which is discharged from the forward or left ends of the cylinders 22 through the line 109, is recirculated through the valve 121, the line 120, valve 116 andthe lines 118 and 119 to the ports 60 in the right ends of these cylinders.

Shortly after the main ram stem 18 begins to advance, the cross head 17 opens the switch MRLS-l (FIGS. 3 and 4), thereby deenergizing the relay CR1, and the solenoids 133 and 126, thus causing the loader 34 to retract and open the switch LLS-l. Relays CR2 and CRP, and solenoids 117 and 106, however, remain energized through the now-closed holding switch CR2-1, which is connected in parallel with the limit switch LLS- 1; and the valves 129 and 130 maintain the pusher rams 82 in their advanced positions.

Before the main ram stem 18 upsets the billet in the container in housing 37, the crosshead 17 closes switch MRLS-6 temporarily, thereby energizing relay CR6 through now-closed switch CR2-5. This closes switch CR61 to hold relay CR6 energized, and opens switch CR6-2 to deenergize solenoid 122. Valve 121 therefore closes, and the main ram continues to be advanced under a back-pressure which may be adjusted through a relief valve 150, as disclosed in my above-identified patent.

As the main ram continues to advance, and after the billet has been pushed at least part-way into the bore of the container 37, the advanced pusher rams 82 engage and commence to push the container housing 37 to the left in FIG. 1 toward the die in unison with the advance of the main ram 18, thereby allowing switch CLS-3 to close. At this time the fluid in the left ends of the cylinders 42 is exhausted through ports 49, lines 114, 113, valve 110 and line 115 to the sump; and fluid under pilot pressure is admitted to the ports 48 in the right ends of these cylinders through a check valve 153. The relief valve 129 is set just high enough to overcome the inertia of the container housing 37, when it is first engaged by the extended rams 82. As a result, the fluid behind the inner ends 94 of the rams 82 cushions the initial contact between the container housing 37 and the pusher rams 82, and transmits the forward movement of the main ram 18 to the container.

As it approaches the die, and while it is still spaced from the die in a position corresponding to the belowdescribed stripping position, the rod 140 on the container housing closes the limit switch CLS-l. Since the relay CR2 is energized, the switch CR2- 2 is open, so that this initial closing of the limit switch CLS-l has no immediate effect upon the operation of the press. The main ram thus continues to move the container housing 37 until the latter contacts the face of the die and can move no further, at which point it will also have closed the limit switch CLS-2, thus energizing relay CR3. Relay CR3 closes the time delay opening switch CR3-1, but this also has no immediate effect upon the operation of the press. As a result, the main ram stem 18 continues to advance, thus forcing the billet into the die; and the now-stationary container housing 37 forces the pusher rams 82 into the bores of piston rods 24, increasing the pressure in the fluid behind the inner ends 94 of the pusher rams to a value in excess of the setting of the relief valve 129, whereby the latter is forced open to permit the rams to retract into the rods 24 as the billet is extruded through the die.

When the main ram reaches its extreme advanced position, the cross head 17 opens the limit switch MRLS-2 to deenergize relays CR2 and CRP, thereby reversing the output of the pumps P so that fluid now flows from ports A to ports B, returning switches CR2-1, CR2-2, CR2-3, CR24 and 0R2-5 to the positions illustrated in FIG. 4. The opening of switch CR2-5 prevents relay CR6 from being energized on the return movement of the main ram. Solenoids 108 and 122 are now energized through switches MRLS-S, CR5-3 and CR2-3 to close valve 107 and to open valve 121. At the same time, the cross head 17 also closes switch MRLS-3 to energize relay CR4 through the now-closed relay switch CR3-1, thereby energizing the solenoid 112, and maintaining the solenoids 117 and 106 energized, through the now-closed switches CLS-3 and CR4-1. As a result, the valve 110 is shifted so that fluid is supplied from the line 100, through valve 110 and lines 113 and 114 to the rear ends of the cylinders 42 to move the container housing 37 in a return direction, or towards the right in FIGS. 1 and 3. Since the container housing is in contact with the retracted pusher rams 82, the motion of the container housing is transmitted to the main ram stem 18, which returns (to the right in FIGS. 1 and 3) in unison with the container housing 37, so that switches CLS-2 and MRLS-3 open simultaneously.

During the initial portion of the return movement the fluid in the right ends of the side cylinders 22 flows through the lines 119 and 118, valve 116 and line 101 to the ports B and the pumps P. Although the relay CR3 is deenergized upon the movement of the container away from the face of the die, the relay CR4 and solenoids 112, 117 and 106 remain energized through the now-closed switches CR4-2 (holding), CR3-1 (time delayed opening), CLS-3 and CR4-1. Some of the fluid exhausted from right ends of the cylinders 22 circulates through line 120, the now-open valve 121, and line 109 to the left ends of the cylinders as the pistons therein are moved to the right by the initial return movement of the container housing 37 After the container housing and the main ram stem 18 have retracted far enough to reach the stripping position, the time-delay switch CR31 finally opens. Since switch CR5-2 is also open at this time, the relay CR4 and the solenoids 112, 117 and 106 are deenergized, so that valve 110 returns to the position shown in FIG. 3, valve 116 closes to prevent further discharge of fluid from the right ends of the cylinders 22, and valve 105 is opened to permit fluid to recirculate through the pumps P from line to line 101. This stops the return movement of the main ram stem 18 and the container housing 37. Also at this time, the switch CR4-4 closes, and through the still- 7 closed switch CLS-l, and the closed relay switches CR4- 3 (time delayed opening) and C-R2-2, energizes the solenoid 132, thereby shifting the valve 134 to actuate the shear 28. The shear 28 thus advances to strip the butt end of the billet in conventional manner.

As the shear 28 begins to advance, it permits the switch SLS-l to close, so that when the time-delayed opening switch CR4-3 thereafter opens, the solenoid 132 remains energized until the shear 28 reaches its advanced position. When shear 28 reaches its advanced position, it closes the limit switch SLS-2 momentarily, thus energizing the relay CR5, which closes switch CR-2, thereby reenergizing the relay CR4, and solenoids 112, 117 and 106 through switches CLS-3 and CR4-1. Switch CR4-4 thus opens to denergize the solenoid 132, so that the shear 28 is retracted. Upon the retraction of the shear 28, relay CR5 remains energized through the holding switch CR5-1 and the limit switch MRLS4. Relay CR5 also opens switch CR5-3 to deenergize solenoids 108 and 122, thereby opening valve 107 and closing valve 121.

The container housing 37 once again begins to push the main ram stem 18 toward the right in FIGS. 1 and 3 until the container reaches its extreme retracted position where its rod 140 opens switch CLS-3 thereby deenergizing the solenoid 112 so that the container stops. The main ram stem 18, however, continues to retract toward the right in FIGS. 3 and 4 as a result of fluid which is forced from the ports A in the pumps P, through the line 100, now open valve 107 and line 109 to the left ends of the positioning cylinders 22. When the main ram stem 18 reaches its fully retracted position, the cross head 17 opens the limit switches MRLS-4 and MRLS-S, thereby maintaining solenoids 108 and 122 deenergized, and deenergizing the relay CR5 so that the switch CR5-2 opens. This deenergizes the relay CR4, and hence the solenods 117 and 106. The valves and switches are thus returned to the positions illustrated in FIGS. 3 and 4; and the cycle is complete.

From the foregoing it will be apparent that applicant has devised a relatively simple means for absorbing the shock upon contact of the advancing main ram with the container housing, and for coordinating the movements of these two parts so that they move, as far as possible, in unison with one another during both the advance and return of the main ram. This insures a fast extrusion cycle with minimum sized pumps; and considerably increases the efficiency of operation of the press as compared with prior, like presses.

Although in the illustrated embodiment the pusher rams 82 are advanced by fluid which is controlled by a solenoid operated valve 125, it is to be understood that, if desired, fluid at pilot pressure may be constantly applied through the check valve 130 to the bores 80 in the piston rods 24, so that the rams 82 will be made to advance whenever the pressure of the fluid in the bores 80 is below the maximurrr pressure for which the relief valve 129 is set. Moreover, it is the practice to set the relief valve 129 so that the fluid applied to the bores 80 will be insuificient to move, by itself, either the container or the main ram, respectively. Moreover, the solenoid 111 may be connected with a manually operable switch (not illustrated) for operating the valve 110 in such manner as to effect the reaction of the container 37 independently of the movement of the main ram 18.

While the invention has with a specific embodiment been described in connection thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. An extrusion press comprising a die,

a ram,

a billet container positioned between said die and ram and normally spaced from said die, and

means for reciprocating said ram and container toward and away from said die from and to retracted positions in which said ram and container are spaced from one another and from said die, and

movable means interposed between the confronting ends of said ram and said container and operative during advance of said ram toward said die to transmit movement of said ram to said container thereby to advance said container into contact with said die, and operative during movement of said container away from said die to transmit the movement of said container to said ram to retract said container and ram in unison away from said die,

said movable means comprising a fluid pressure operated telescopic member, and

control means whereby said telescopic member is in its advanced position, when said ram advances toward said container.

2. An extrusion press as defined in claim 1, wherein (a) said telescopic member is reciprocably mounted in and projects from one of said confronting ends of said ram and container, respectively, and is engageable by the other of said ends, when said ram and container are moved to their advanced positions, and

(b) means including a relief valve resisting retraction of said telescopic member.

3. An extrusion press as defined in claim 2, including (a) means for continuing to advance said rarn toward said die after the engagement of said container with said die, and

(b) means to continue the retraction of said ram away from said die and said container, after said container has reached its retracted position.

4. An extrusion press comprising a die, a ram, and a billet container positioned between said die and ram and normally spaced from said die, and having means for reciprocating said ram and container toward and away from said die from and to retracted positions in which said ram and container are spaced from one another and from said die,

movable means interposed between the confronting ends of said ram and said container and operative during advance of said ram toward said die to transmit movement of said ram to said container thereby to advance said container into contact with said die, and operative during the movement of said container away from said die to transmit the movement of said container to said ram to retract said container and ram in unison away from said die,

said reciprocating means comprising a first cylinder having therein a first piston connected by a first rod to said ram,

a second cylinder having therein a second piston connected by a second rod to said container,

first valve means for connecting said cylinders to a supply of fluid under pressure for reciprocating said pistons in said cylinders, and

means for controlling said valve means to cycle said ram and said container from their retracted positions to their advanced positions, and back to their retracted positions,

. further means effective to cause said reciprocating means to advance said ram toward said container, while the latter is in its retracted position, to continue to advance said ram after said container has reached its advanced position, and to continue to retract said ram after said container has returned to its retracted position,

said movable means comprising a third piston mounted to reciprocate in a bore in one of said first and second rods,

a third rod secured to said third piston for reciprocation therewith between retracted and advanced positions, and

second valve means connecting said bore to said supply of fluid and operative, when said ram and container are moved to their retracted positions, to move said third piston in a direction to advance said third rod into the space between said ram and container to be engaged by one of the confronting ends of said ram and container, respectively, upon the advance of said ram toward said die.

5. An extrusion press as defined in claim 4, wherein said second valve means includes a relief valve operative, when said container has reached its advanced position, to permit said ram to force said third rod into its retracted position during the continued advance of said ram.

6. An extrusion press as defined in claim 4, wherein said second valve means comprises,

(a) a check valve permitting unidirectional flow of fluid from said supply to said bore, and

(b) a relief valve between said check valve and said bore operative to exhaust fluid from said bore when the pressure of the fluid in said bore exceeds a predetermined value.

7. An extrusion press comprising a die, a ram, and a billet container positioned between said die and ram and normally spaced from said die, and having means for reciprocating said ram and container toward and away from said die from and to retracted positions in which said ram and container are spaced from one another and from said die,

movable means interposed between the confronting ends of said ram and said container and operative during advance of said ram toward said die to transmit movement of said ram to said container thereby to advance said container into contact with said die, and operative during the movement of said container away from said die to transmit the movement of said container to said ram to retract said container and ram in unison away from said die,

a first pair of piston rods mounted to reciprocate in a first pair of spaced, parallel cylinders disposed at opposite sides of, and parallel to said ram, said rods being connected to said ram for reciprocation therewith,

a second pair of rods mounted to reciprocate in a second pair of spaced, parallel cylinders, and connected to said container to reciprocate therewith parallel to said ram,

said movable means comprises a third pair of rods carried by one of the two first-named pairs of rods, each of the rods of said third pair being reciprocable in a bore in one of the rods of said one pair, and being engageable with one of the confronting ends of said container and ram, respectively,

each of the rods of said one pair having therein a port for supplying fluid to, and exhausting fluid from, its bore, and

first valve means operative, when said ram is in its retracted position, to supply fluid under pressure through said ports to said bores to advance said third pair of rods into the space between said confronting ends of said container and ram, and releasably to lock said third pair of rods in their advanced positions.

8. An extrusion press as defined in claim 7, wherein (a) second valve means is operable to connect said first pair of cylinders to said supply to advance said ram toward said container, while said container is in its retracted position, thereby to engage said third pair of rods against one of the confronting ends of said container and ram, respectively, and thereby to urge said container against said die during the advance of said ram,

(b) said second valve means is operable to continue advance of said ram toward said die after the engagement of said container with said die, and

(c) said first valve means is operative during said continued advance of said ram to permit said third pair of rods to be urged into their retracted positions in said bores.

9. An extrusion press as defined in claim 8, wherein said first valve means comprises (a) a solenoid-operated valve for supplying fluid under pressure to said ports,

(b) a check valve interposed between said solenoidoperated valve and said ports to prevent the fluid from being exhausted from said bores through the last-named Valve, and

(c) a relief valve interposed between said check valve and said ports and operative to exhaust fluid from said bores during said continued advance of said ram after said container has contacted said die.

10. Apparatus as defined in claim 8, wherein (a) third valve means is operative, when said ram reaches its advanced position, to connect said second pair of cylinders to said supply, thereby to retract said container, whereby the movement of said container is imparted through said third pair of rods to said ram, and

(b) means is operative to continue to retract said ram to its retracted position after said container has reached its retracted position.

11. An extrusion press comprising a die,

a rectilinearly reciprocable billet container,

said container aligned rectilinearly with said ram and being positioned between said ram and said die and being normally spaced from both said ram and said die,

fluid-pressure operated means tory movement of said ram,

cushioning means interposed between the confronting ends of said ram and said container and operative to transmit movement of said ram to said container, during advance of said ram toward said die, until said container engages said die, and

means for retracting said container from said die and operative to transmit the retracting movement of said container to said ram until said container has returned to its normal position.

for eflecting reciproca- References Cited UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 

